1. Technical Field
The present invention relates to an optical fiber head which has a leading end portion of an optical fiber and an optical element held by a casing, and particularly to an optical fiber head which can be preferably used as a head for a fiber optic optoelectronic switch.
2. Related Art
The optical fiber head is for appropriately performing light beam control on light to be emitted from a leading end face of the optical fiber or light entered the leading end face of the optical fiber by an optical element, and is configured to have the leading end face of the optical fiber and a back end face of the optical element arranged to face each other by making the casing hold the leading end portion of the optical fiber and the optical element. Here, a lens, a mirror, a polarization filter, an aperture, or the like is generally used as the optical element.
In the optical fiber head, it is required for the optical fiber and the optical element to be highly precisely aligned and fixed to the casing so that the optical axis of the optical fiber matches with the optical center of the optical element. Insufficient alignment prevents the optical fiber from providing desired optical properties, thus decreasing a yield.
Therefore, adhesives or crimping rings are conventionally used to fix the optical fiber to the casing so as to highly precisely fix the optical fiber to the casing. For example, JP 6-160668 A discloses an optical fiber head which has an adhesive used in fixing the optical fiber to the casing, and JP 62-10343 A discloses an optical fiber head which has a crimping ring used in fixing the optical fiber to the casing.
As discussed in JP 6-160668 A, in the case where the optical fiber is fixed to the casing with the adhesive, a core wire which includes a core and a clad is usually exposed at the leading end portion of the optical fiber so that the core wire is fixed to the casing with the adhesive.
On the other hand, as discussed in JP 62-10343 A, in the case where the optical fiber is fixed to the casing with the crimping ring, the core wire is usually kept covered with a coating at the leading end portion of the optical fiber, so that the optical fiber together with the coating is fixed to the casing by the crimping ring.
However, in the case where an adhesive is used to fix the optical fiber to the casing, it is required processes such as exposing the core wire, applying the adhesive to the core wire, and having the adhesive cured. That complicates the assembly operation, and accordingly, raises the manufacturing cost. Further, in order to ensure the sufficient holding power of the casing to hold the optical fiber, it is required to strictly control matters such as the application quantity of the adhesive and the cure condition. That also raises the manufacturing cost.
On the other hand, in the case where a crimping ring is used to fix the optical fiber to the casing, a process of exposing the core wire is not needed. As a result, the assembly operation becomes relatively simple, though, the number of parts increases, which also raises the manufacturing cost. In order to ensure the sufficient holding power of the casing to hold the optical fiber, it is required to strictly control accuracy of dimension of the parts including the crimping ring. That also raises the manufacturing cost.